Wireless communication using several frequency bandwidths has been performed. Presently, a switch circuit IC is obtained by integrating a plurality of high-frequency switches into one-package is used in this application. When communication is performed using a selected signal frequency bandwidth, a signal path of the selected frequency bandwidth is switched on and a signal path of a non-selected signal frequency bandwidth (that is, the one not being presently used for signal transmission) is switched off. As such, there is a possibility that a power supply potential that is supplied to a signal path through which communication is performed (the selected signal path) may temporarily vary, and that, in consequence, insertion loss and high-frequency characteristics of the high-frequency switch will be temporarily degraded.